Formed by membranes joining thus creating a barrier
Effectiveness of the junction based of strength of connection
Functions of Tight Junctions:
Holding the cells together
Preventing movement of certain membrane proteins in order to maintain fuctions of the apical and basolateral areas of the cell (i.e. endocytosis and exocytosis)
Prevent molecules and ions from traveling through the space between cells --> force them to go into cell's membranes by diffusion or active transport in order to go through. Grants control over what can pass through (blood-brain barrier).
Desmosomes
Cell structure designed for cell-cell adhesion
Located randomly around plasma membrane
Prevent separation in cells
Made up of adhesion and linking proteins
Found often in muscle tissue
Desmosome
Gap Junctions
Cell to cell connection for some animal cells
Connects the cytoplasms of both cells
Gap junctions in vertebrates made up of connexin proteins
Gap junctions in invertebrates made up of innexin proteins
Functions of Gap Junctions:
Provide direct transport of molecules
Allows electrical and chemical communication between cells (i.e. electrical synapse in neurons, contraction in heart muscle cells, regulating proliferation and differentiation in skin cells)
Prevent molecules from escaping into intercellular space
Gap Junctions
Symplastic transport
Plasmodesmata
Similar to gap junctions in animal cells
Allow symplastic transport between plant cells (bypass cell wall)
Plant cells can utilize active or passive transport to transfer molecules
Research:
"The UWO Group in Gap Junctions and Disease (the "Gap Junction Group") is the largest group of researchers in Canada studying the involvement of gap junctions (intercellular communication channels) in development and disease."
Dr. Dale Laird, Dr. Christian Naus, and Dr. Gerald Kidder founded the group in 1997.
"Dr. Laird’s expertise in gap junction cell biology complemented Dr. Naus’ interest in the role of gap junctions in cancer and in the central nervous system, and Dr. Kidder's work exploring the roles of gap junctions in embryogenesis and gametogenesis."
Their research has many branches, including mutations in intercellular communication leading to diseases.
Cell Walls of Plants
Plant Cell Walls
I.Primary Cell Wall
a. Structure 1.A plant cell is surrounded by a wall that is rich in polysaccharides (cellulose, hemicellulose and pectin.) 2.This wall helps form the apoplast is the space outside of the plasma membrane between connected plant cell walls. 3.Water and solutes can be transported via the apoplast. 4.The symplast is the space within the plasma membrane that also allows water and solutes to diffuse. 5.Plasmodesmata are small tubes that connect the cytoplasm of neighboring plant cells. 6.The symplast is able to transport water and solutes because of the plasmodesmata. b.Function 1.The cell walls of a plant determine its shape and rate of growth. 2.They create the structure of the plant. 3.They also regulate the diffusion of water and solutes (as mentioned above.) 4.Plant cell walls protect the plant from environmental forces (wind, weather, etc.), and protect the plant against dehydration and pathogens (germs.)
II.Secondary Cell Wall a.Structure 1.The secondary cell wall in a plant is made up of layers of cellulose (with the oldest forming the primary cell wall and the newest forming the secondary cell wall.) 2.The secondary cell wall in a plant forms when the plant cell has stopped growing. 3.Cell division occurs within the primary wall and explains why the secondary wall forms after the cell has stopped growing because there is no more need for expansion due to cell reproduction. 4.It is much stronger and thicker that the primary cell wall. b.Function 1.Allows the plant to grow upward. 2.It also transports materials. III. “Pectin synthesis studies resulted in the identification of the first functionally proven pectin biosynthetic enzyme, galacturonosyltransferase 1 (GAUT1) (http://www.csrees.usda.gov/funding/nri/highlights/2007_no3.pdf). a.Information about the Research Study 1.“Debra Mohnen, Department of Biochemistry and Molecular Biology and Complex Carbohydrate Research Center, University of Georgia, GA” (http://www.csrees.usda.gov/funding/nri/highlights/2007_no3.pdf) 2.National Research Initiative Competitive Grants Program, NRI Research Highlights 3.GAUT 1 was discovered in Arabidopsis thaliana. 4.It synthesizes homogalacturononan or HG. 5.“GAUT1 is part of a family of GAUT1-related genes, which the researchers propose encode galacturonosyltransferases involved in the synthesis of pectin and other cell wall polysaccharides and proteoglycans” (http://www.csrees.usda.gov/funding/nri/highlights/2007_no3.pdf). 6.GAUT 1 is found in these plants: rice, maize, switchgrass, soybeans, and chickpeas. 7.“Pectin biosynthesis appears to occur in protein complexes, at least some of which contain multiple members of the GAUT1-related protein family. These results suggest that the final structure of a pectin will depend on the composition of such biosynthetic enzyme complexes” (http://www.csrees.usda.gov/funding/nri/highlights/2007_no3.pdf). 8.Why is this important? The research of GUAT 1 related genes can help to modify plant cell walls to generate the biomass for fuel production. 9.Biomass refers to living and recently dead biological material that can be used as fuel or for industrial production.
Intercellular Junctions
Cameron BogleThree Types of Junctions:
Tight Junctions
Functions of Tight Junctions:
Desmosomes
Gap Junctions
Functions of Gap Junctions:
Plasmodesmata
Research:
"The UWO Group in Gap Junctions and Disease (the "Gap Junction Group") is the largest group of researchers in Canada studying the involvement of gap junctions (intercellular communication channels) in development and disease."Dr. Dale Laird, Dr. Christian Naus, and Dr. Gerald Kidder founded the group in 1997.
"Dr. Laird’s expertise in gap junction cell biology complemented Dr. Naus’ interest in the role of gap junctions in cancer and in the central nervous system, and Dr. Kidder's work exploring the roles of gap junctions in embryogenesis and gametogenesis."
Their research has many branches, including mutations in intercellular communication leading to diseases.
Cell Walls of PlantsI. Primary Cell Wall
a. Structure1. A plant cell is surrounded by a wall that is rich in polysaccharides (cellulose, hemicellulose and pectin.)
2. This wall helps form the apoplast is the space outside of the plasma membrane between connected plant cell walls.
3. Water and solutes can be transported via the apoplast.
4. The symplast is the space within the plasma membrane that also allows water and solutes to diffuse.
5. Plasmodesmata are small tubes that connect the cytoplasm of neighboring plant cells.
6. The symplast is able to transport water and solutes because of the plasmodesmata.
b. Function
1. The cell walls of a plant determine its shape and rate of growth.
2. They create the structure of the plant.
3. They also regulate the diffusion of water and solutes (as mentioned above.)
4. Plant cell walls protect the plant from environmental forces (wind, weather, etc.), and protect the plant against dehydration and pathogens (germs.)
II. Secondary Cell Wall
a. Structure
1. The secondary cell wall in a plant is made up of layers of cellulose (with the oldest forming the primary cell wall and the newest forming the secondary cell wall.)
2. The secondary cell wall in a plant forms when the plant cell has stopped growing.
3. Cell division occurs within the primary wall and explains why the secondary wall forms after the cell has stopped growing because there is no more need for expansion due to cell reproduction.
4. It is much stronger and thicker that the primary cell wall.
b. Function
1. Allows the plant to grow upward.
2. It also transports materials.
III. “Pectin synthesis studies resulted in the identification of the first functionally proven pectin biosynthetic enzyme,
galacturonosyltransferase 1 (GAUT1) (http://www.csrees.usda.gov/funding/nri/highlights/2007_no3.pdf).
a. Information about the Research Study
1. “Debra Mohnen, Department of Biochemistry and Molecular Biology and Complex Carbohydrate Research Center, University of Georgia, GA” (http://www.csrees.usda.gov/funding/nri/highlights/2007_no3.pdf)
2. National Research Initiative Competitive Grants Program, NRI Research Highlights
3. GAUT 1 was discovered in Arabidopsis thaliana.
4. It synthesizes homogalacturononan or HG.
5. “GAUT1 is part of a family of GAUT1-related genes, which the researchers propose encode galacturonosyltransferases involved in the synthesis of pectin and other cell wall polysaccharides and proteoglycans” (http://www.csrees.usda.gov/funding/nri/highlights/2007_no3.pdf).
6. GAUT 1 is found in these plants: rice, maize, switchgrass, soybeans, and chickpeas.
7. “Pectin biosynthesis appears to occur in protein complexes, at least some of which contain multiple members of the GAUT1-related protein family. These results suggest that the final structure of a pectin will depend on the composition of such biosynthetic enzyme complexes” (http://www.csrees.usda.gov/funding/nri/highlights/2007_no3.pdf).
8. Why is this important? The research of GUAT 1 related genes can help to modify plant cell walls to generate the biomass for fuel production.
9. Biomass refers to living and recently dead biological material that can be used as fuel or for industrial production.